In an effort to deliver more premium electronic devices to consumers, cellular phone manufacturers are increasingly using exterior cosmetic housings fabricated from metal alloys. However, the use of metal for an exterior housing in high capability phones or “smartphones” currently requires complex manufacturing techniques. For example, one technique that is used to provide a metal exterior while maintaining the electrical isolation needed by current antenna technology requires the manufacturer to form a single metal housing which is then separated into multiple pieces which are held together by a plastic resin. In particular, the plastic divisions in the metal allow the separate exterior metal pieces to act as antennas while maintaining separation from each other and/or from grounded pieces of metal.
While this technique may provide the needed electrical isolation, it does so at the expense of device integrity. Significant metal to plastic interlock geometry is required to keep the plastic and metal from detaching, and the multiple plastic divisions are cosmetically undesirable. Moreover, only certain grades of plastic may be used, since the plastic must typically survive subsequent processing steps such as molding, anodizing and so on. This limit on usable plastics may also limit other aspects of the device such as color. Moreover, when plastic divisions run across the full width of a device, a double wall section (metal plus plastic) contributes to device thickness.
Finally, it will be appreciated that such devices often require I/O (input/output) ports to fall in the middle of a functional antenna element. Not only does this placement physically disrupt the antenna element, but it may also lead to coupling between the antenna element and the port, requiring that additional precautions be taken.
Certain other devices use a perimeter metal housing instead of a full metal back housing. However, this configuration does not solve the above-noted deficiencies. For example, the corners of the housing in these devices are often used as antennas, and therefore four or more perimeter separators of nonconductive material are needed to isolate the four antennas.
While the present disclosure is directed to a system that can eliminate some of the shortcomings noted in this Background section, it should be appreciated that any such benefit is not a limitation on the scope of the disclosed principles, nor of the attached claims, except to the extent expressly noted in the claims. Additionally, the discussion of technology in this Background section is reflective of the inventors' own observations, considerations, and thoughts, and is in no way intended to accurately catalog or comprehensively summarize the prior art. As such, the inventors expressly disclaim this section as admitted or assumed prior art with respect to the discussed details. Moreover, the identification herein of a desirable course of action reflects the inventors' own observations and ideas, and should not be assumed to indicate an art-recognized desirability.